On the other hand, in the diffusive part, a Symmetric Interior Penalty (SIP) approach has been adopted for the space discretization [1]}. Moreover, following [2]}, we set for each face \(\Gamma \)  of a cell \(K\)
\(\sigma _{\Gamma ,K} = \left(k+1\right)^2\frac{\text{diam}\left(\Gamma \right)}{\text{diam}\left(K\right)}\) 
